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/**
* @file depend_scope.c
* @author Ambroz Bizjak <ambrop7@gmail.com>
*
* @section LICENSE
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the author nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* @section DESCRIPTION
*
* Multiple-option dependencies module.
*
* Synopsis:
* depend_scope()
*
* Description:
* A scope for dependency names. Any dependency names used in provide() and depend()
* methods on this object are local to this object. Contrast to the multidepend module,
* which provides the same functionality as this module, but with a single global
* dependency name scope.
*
* Synopsis:
* depend_scope::provide(name)
*
* Arguments:
* name - provider identifier
*
* Description:
* Satisfies a dependency.
* If any depend()'s get immediately bound to this provide(),
* the side effects of those first happen, and only then can the process of this
* provide() continue.
* When provide() is requested to deinitialize, if there are any depend()'s bound,
* provide() will not finish deinitializing until all the processes containing the
* bound depend()'s have backtracked to the point of the corresponding depend().
* More specifically, when backtracking has finished for the last bound depend(),
* first the immediate effects of the provide() finshing deinitialization will happen,
* and only then will the depend() attempt to rebind. (If the converse was true, the
* depend() could rebind, but when deinitialization of the provide()'s process
* continues, lose this binding. See ncd/tests/depend_scope.ncd .)
*
* Synopsis:
* depend_scope::depend(list names)
*
* Arguments:
* names - list of provider identifiers. Names more to the beginning are considered
* more desirable.
*
* Description:
* Binds to the provide() providing one of the specified dependency names which is most
* desirable. If there is no provide() providing any of the given dependency names,
* waits and binds when one becomes available.
* If the depend() is bound to a provide(), and the bound provide() is requested to
* deinitize, or a more desirable provide() becomes available, the depend() statement
* will go down (triggering backtracking), wait for backtracking to finish, and then
* try to bind to a provide() again, as if it was just initialized.
* When depend() is requested to deinitialize, it deinitializes immediately.
*
* Attributes:
* Exposes objects as seen from the corresponding provide.
*/
#include <stdlib.h>
#include <string.h>
#include <misc/offset.h>
#include <misc/debug.h>
#include <misc/balloc.h>
#include <misc/BRefTarget.h>
#include <structure/LinkedList1.h>
#include <ncd/module_common.h>
#include <generated/blog_channel_ncd_depend_scope.h>
struct scope {
BRefTarget ref_target;
LinkedList1 provides_list;
LinkedList1 depends_list;
};
struct scope_instance {
NCDModuleInst *i;
struct scope *scope;
};
struct provide {
NCDModuleInst *i;
struct scope *scope;
NCDValRef name;
LinkedList1Node provides_list_node;
LinkedList1 depends_list;
int dying;
};
struct depend {
NCDModuleInst *i;
struct scope *scope;
NCDValRef names;
LinkedList1Node depends_list_node;
struct provide *provide;
LinkedList1Node provide_depends_list_node;
int provide_collapsing;
};
static struct provide * find_provide (struct scope *o, NCDValRef name)
{
for (LinkedList1Node *ln = LinkedList1_GetFirst(&o->provides_list); ln; ln = LinkedList1Node_Next(ln)) {
struct provide *provide = UPPER_OBJECT(ln, struct provide, provides_list_node);
ASSERT(provide->scope == o)
if (NCDVal_Compare(provide->name, name) == 0) {
return provide;
}
}
return NULL;
}
static struct provide * depend_find_best_provide (struct depend *o)
{
size_t count = NCDVal_ListCount(o->names);
for (size_t j = 0; j < count; j++) {
NCDValRef name = NCDVal_ListGet(o->names, j);
struct provide *provide = find_provide(o->scope, name);
if (provide && !provide->dying) {
return provide;
}
}
return NULL;
}
static void depend_update (struct depend *o)
{
// if we're collapsing, do nothing
if (o->provide && o->provide_collapsing) {
return;
}
// find best provide
struct provide *best_provide = depend_find_best_provide(o);
ASSERT(!best_provide || !best_provide->dying)
// has anything changed?
if (best_provide == o->provide) {
return;
}
if (o->provide) {
// set collapsing
o->provide_collapsing = 1;
// signal down
NCDModuleInst_Backend_Down(o->i);
} else {
// insert to provide's list
LinkedList1_Append(&best_provide->depends_list, &o->provide_depends_list_node);
// set not collapsing
o->provide_collapsing = 0;
// set provide
o->provide = best_provide;
// signal up
NCDModuleInst_Backend_Up(o->i);
}
}
static void scope_ref_target_func_release (BRefTarget *ref_target)
{
struct scope *o = UPPER_OBJECT(ref_target, struct scope, ref_target);
ASSERT(LinkedList1_IsEmpty(&o->provides_list))
ASSERT(LinkedList1_IsEmpty(&o->depends_list))
BFree(o);
}
static void scope_func_new (void *vo, NCDModuleInst *i, const struct NCDModuleInst_new_params *params)
{
struct scope_instance *o = vo;
o->i = i;
// pass scope instance pointer to methods not NCDModuleInst pointer
NCDModuleInst_Backend_PassMemToMethods(i);
// read arguments
if (!NCDVal_ListRead(params->args, 0)) {
ModuleLog(i, BLOG_ERROR, "wrong arity");
goto fail0;
}
// allocate scope
o->scope = BAlloc(sizeof(*o->scope));
if (!o->scope) {
ModuleLog(i, BLOG_ERROR, "BAlloc failed");
goto fail0;
}
// init reference target
BRefTarget_Init(&o->scope->ref_target, scope_ref_target_func_release);
// init provide and depend lists
LinkedList1_Init(&o->scope->provides_list);
LinkedList1_Init(&o->scope->depends_list);
// go up
NCDModuleInst_Backend_Up(i);
return;
fail0:
NCDModuleInst_Backend_DeadError(i);
}
static void scope_func_die (void *vo)
{
struct scope_instance *o = vo;
// release scope reference
BRefTarget_Deref(&o->scope->ref_target);
NCDModuleInst_Backend_Dead(o->i);
}
static void provide_func_new (void *vo, NCDModuleInst *i, const struct NCDModuleInst_new_params *params)
{
struct provide *o = vo;
o->i = i;
o->scope = ((struct scope_instance *)params->method_user)->scope;
// read arguments
NCDValRef name_arg;
if (!NCDVal_ListRead(params->args, 1, &name_arg)) {
ModuleLog(i, BLOG_ERROR, "wrong arity");
goto fail0;
}
// remember name
o->name = name_arg;
// check for existing provide with this name
if (find_provide(o->scope, o->name)) {
ModuleLog(o->i, BLOG_ERROR, "a provide with this name already exists");
goto fail0;
}
// grab scope reference
if (!BRefTarget_Ref(&o->scope->ref_target)) {
ModuleLog(o->i, BLOG_ERROR, "BRefTarget_Ref failed");
goto fail0;
}
// insert to provides list
LinkedList1_Append(&o->scope->provides_list, &o->provides_list_node);
// init depends list
LinkedList1_Init(&o->depends_list);
// set not dying
o->dying = 0;
// signal up.
// This comes above the loop which follows, so that effects on related depend statements are
// computed before this process advances, avoiding problems like failed variable resolutions.
NCDModuleInst_Backend_Up(o->i);
// update depends
for (LinkedList1Node *ln = LinkedList1_GetFirst(&o->scope->depends_list); ln; ln = LinkedList1Node_Next(ln)) {
struct depend *depend = UPPER_OBJECT(ln, struct depend, depends_list_node);
depend_update(depend);
}
return;
fail0:
NCDModuleInst_Backend_DeadError(i);
}
static void provide_free (struct provide *o)
{
ASSERT(LinkedList1_IsEmpty(&o->depends_list))
// remove from provides list
LinkedList1_Remove(&o->scope->provides_list, &o->provides_list_node);
// release scope reference
BRefTarget_Deref(&o->scope->ref_target);
NCDModuleInst_Backend_Dead(o->i);
}
static void provide_func_die (void *vo)
{
struct provide *o = vo;
ASSERT(!o->dying)
// if we have no depends, die immediately
if (LinkedList1_IsEmpty(&o->depends_list)) {
provide_free(o);
return;
}
// set dying
o->dying = 1;
// start collapsing our depends
for (LinkedList1Node *ln = LinkedList1_GetFirst(&o->depends_list); ln; ln = LinkedList1Node_Next(ln)) {
struct depend *depend = UPPER_OBJECT(ln, struct depend, provide_depends_list_node);
ASSERT(depend->provide == o)
// update depend to make sure it is collapsing
depend_update(depend);
}
}
static void depend_func_new (void *vo, NCDModuleInst *i, const struct NCDModuleInst_new_params *params)
{
struct depend *o = vo;
o->i = i;
o->scope = ((struct scope_instance *)params->method_user)->scope;
// read arguments
NCDValRef names_arg;
if (!NCDVal_ListRead(params->args, 1, &names_arg)) {
ModuleLog(i, BLOG_ERROR, "wrong arity");
goto fail0;
}
if (!NCDVal_IsList(names_arg)) {
ModuleLog(o->i, BLOG_ERROR, "wrong type");
goto fail0;
}
// remember names
o->names = names_arg;
// grab scope reference
if (!BRefTarget_Ref(&o->scope->ref_target)) {
ModuleLog(o->i, BLOG_ERROR, "BRefTarget_Ref failed");
goto fail0;
}
// insert to depends list
LinkedList1_Append(&o->scope->depends_list, &o->depends_list_node);
// set no provide
o->provide = NULL;
// update
depend_update(o);
return;
fail0:
NCDModuleInst_Backend_DeadError(i);
}
static void depend_func_die (void *vo)
{
struct depend *o = vo;
if (o->provide) {
// remove from provide's list
LinkedList1_Remove(&o->provide->depends_list, &o->provide_depends_list_node);
// if provide is dying and is empty, let it die
if (o->provide->dying && LinkedList1_IsEmpty(&o->provide->depends_list)) {
provide_free(o->provide);
}
}
// remove from depends list
LinkedList1_Remove(&o->scope->depends_list, &o->depends_list_node);
// release scope reference
BRefTarget_Deref(&o->scope->ref_target);
NCDModuleInst_Backend_Dead(o->i);
}
static void depend_func_clean (void *vo)
{
struct depend *o = vo;
if (!(o->provide && o->provide_collapsing)) {
return;
}
// save provide
struct provide *provide = o->provide;
// remove from provide's list
LinkedList1_Remove(&provide->depends_list, &o->provide_depends_list_node);
// set no provide
o->provide = NULL;
// update
depend_update(o);
// if provide is dying and is empty, let it die.
// This comes after depend_update so that the side effects of the
// provide dying have priority over rebinding the depend.
if (provide->dying && LinkedList1_IsEmpty(&provide->depends_list)) {
provide_free(provide);
}
}
static int depend_func_getobj (void *vo, NCD_string_id_t objname, NCDObject *out_object)
{
struct depend *o = vo;
if (!o->provide) {
return 0;
}
return NCDModuleInst_Backend_GetObj(o->provide->i, objname, out_object);
}
static struct NCDModule modules[] = {
{
.type = "depend_scope",
.func_new2 = scope_func_new,
.func_die = scope_func_die,
.alloc_size = sizeof(struct scope_instance)
}, {
.type = "depend_scope::provide",
.func_new2 = provide_func_new,
.func_die = provide_func_die,
.alloc_size = sizeof(struct provide)
}, {
.type = "depend_scope::depend",
.func_new2 = depend_func_new,
.func_die = depend_func_die,
.func_clean = depend_func_clean,
.func_getobj = depend_func_getobj,
.flags = NCDMODULE_FLAG_CAN_RESOLVE_WHEN_DOWN,
.alloc_size = sizeof(struct depend)
}, {
.type = NULL
}
};
const struct NCDModuleGroup ncdmodule_depend_scope = {
.modules = modules
};